メタデータ
| 項目 |
値 |
| Designation |
C/2018 A1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-10-20T10:16:17.644800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:39Z |
| Obs used |
118 |
| NEO |
- |
| M1 |
15.100 |
| K1 |
5.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-02-06.0000000 |
| e |
0.90438598 |
| q (au) |
2.419351 |
| a (au) |
25.303307 |
| i (deg) |
53.559981 |
| Ω (om, deg) |
336.621053 |
| ω (w, deg) |
96.385267 |
| M (ma, deg) |
0.840729 |
等級
散乱 + 全体線形
$$
M_a = (16.981 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
16.981 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.738 |
| k |
0.800 |
| δ90 |
10.000 |
| パラメータ |
記号 |
範囲 |
説明 |
| 太陽・地球距離が1 AUのときの絶対等級 |
H0 |
-5 to 20 |
彗星の固有の明るさ |
| 測光スロープパラメータ |
n |
2 to 6 |
太陽距離に対する明るさ変化率 |
| 前方散乱非対称係数 |
gf |
0.8 to 1 |
前方散乱の強さ |
| 後方散乱非対称係数 |
gb |
-1 to -0.5 |
後方散乱の強さ |
| 分配係数 |
k |
0.8 to 1 |
前方/後方散乱の寄与比 |
| ダスト/ガス明るさ比 |
δ90 |
1 to 10 |
ダスト散乱とガス放射の相対寄与 |
参考: EPSC-DPS2025-160
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
11:56:14.13 |
-53:31:43.9 |
HIP 58255 |
5.68 |
| 2026-03-26 12:00 |
11:56:04.62 |
-53:31:23.0 |
HIP 58255 |
7.00 |
| 2026-03-27 00:00 |
11:55:55.11 |
-53:31:01.4 |
HIP 58255 |
8.37 |
| 2026-03-27 12:00 |
11:55:45.62 |
-53:30:39.1 |
HIP 58255 |
9.77 |
| 2026-03-28 00:00 |
11:55:36.15 |
-53:30:16.1 |
HIP 58255 |
11.17 |
| 2026-03-28 12:00 |
11:55:26.69 |
-53:29:52.4 |
HIP 58255 |
12.59 |
| 2026-03-29 00:00 |
11:55:17.24 |
-53:29:28.0 |
HIP 58255 |
14.02 |
| 2026-03-29 12:00 |
11:55:07.82 |
-53:29:02.9 |
HIP 58144 |
14.99 |
| 2026-03-30 00:00 |
11:54:58.41 |
-53:28:37.1 |
HIP 58144 |
14.93 |
| 2026-03-30 12:00 |
11:54:49.02 |
-53:28:10.7 |
HIP 58144 |
15.00 |
| 2026-03-31 00:00 |
11:54:39.65 |
-53:27:43.6 |
HIP 58144 |
15.20 |
| 2026-03-31 12:00 |
11:54:30.31 |
-53:27:15.8 |
HIP 58144 |
15.54 |
| 2026-04-01 00:00 |
11:54:20.98 |
-53:26:47.4 |
HIP 58144 |
15.98 |
| 2026-04-01 12:00 |
11:54:11.68 |
-53:26:18.3 |
HIP 58144 |
16.54 |
| 2026-04-02 00:00 |
11:54:02.40 |
-53:25:48.5 |
HIP 58144 |
17.20 |
| 2026-04-02 12:00 |
11:53:53.14 |
-53:25:18.1 |
HIP 58144 |
17.94 |
| 2026-04-03 00:00 |
11:53:43.91 |
-53:24:47.0 |
HIP 58144 |
18.76 |
| 2026-04-03 12:00 |
11:53:34.70 |
-53:24:15.3 |
HIP 58144 |
19.65 |
| 2026-04-04 00:00 |
11:53:25.52 |
-53:23:42.9 |
HIP 58144 |
20.60 |
| 2026-04-04 12:00 |
11:53:16.37 |
-53:23:09.9 |
HIP 58144 |
21.60 |
| 2026-04-05 00:00 |
11:53:07.25 |
-53:22:36.3 |
HIP 58144 |
22.65 |
| 2026-04-05 12:00 |
11:52:58.15 |
-53:22:02.0 |
HIP 57916 |
22.49 |
| 2026-04-06 00:00 |
11:52:49.09 |
-53:21:27.1 |
HIP 57916 |
21.83 |
| 2026-04-06 12:00 |
11:52:40.06 |
-53:20:51.5 |
HIP 57916 |
21.23 |
| 2026-04-07 00:00 |
11:52:31.06 |
-53:20:15.4 |
HIP 57916 |
20.72 |
| 2026-04-07 12:00 |
11:52:22.09 |
-53:19:38.6 |
HIP 57916 |
20.28 |
| 2026-04-08 00:00 |
11:52:13.15 |
-53:19:01.2 |
HIP 57916 |
19.94 |
| 2026-04-08 12:00 |
11:52:04.25 |
-53:18:23.2 |
HIP 57916 |
19.69 |
| 2026-04-09 00:00 |
11:51:55.39 |
-53:17:44.6 |
HIP 57916 |
19.54 |
| 2026-04-09 12:00 |
11:51:46.56 |
-53:17:05.4 |
HIP 57916 |
19.49 |
| 2026-04-10 00:00 |
11:51:37.76 |
-53:16:25.6 |
HIP 57916 |
19.54 |
| 2026-04-10 12:00 |
11:51:29.01 |
-53:15:45.2 |
HIP 57674 |
19.15 |
| 2026-04-11 00:00 |
11:51:20.29 |
-53:15:04.2 |
HIP 57674 |
17.69 |
| 2026-04-11 12:00 |
11:51:11.61 |
-53:14:22.6 |
HIP 57674 |
16.23 |
| 2026-04-12 00:00 |
11:51:02.97 |
-53:13:40.5 |
HIP 57674 |
14.77 |
| 2026-04-12 12:00 |
11:50:54.37 |
-53:12:57.7 |
HIP 57674 |
13.32 |
| 2026-04-13 00:00 |
11:50:45.82 |
-53:12:14.4 |
HIP 57674 |
11.86 |
| 2026-04-13 12:00 |
11:50:37.30 |
-53:11:30.6 |
HIP 57674 |
10.42 |
| 2026-04-14 00:00 |
11:50:28.83 |
-53:10:46.2 |
HIP 57674 |
8.97 |
| 2026-04-14 12:00 |
11:50:20.40 |
-53:10:01.2 |
HIP 57674 |
7.54 |
| 2026-04-15 00:00 |
11:50:12.02 |
-53:09:15.7 |
HIP 57674 |
6.11 |
| 2026-04-15 12:00 |
11:50:03.69 |
-53:08:29.6 |
HIP 57674 |
4.72 |
| 2026-04-16 00:00 |
11:49:55.40 |
-53:07:43.0 |
HIP 57674 |
3.38 |